DESCRIPTION: Glaucoma is a progressive disease known to affect the vision in more than 2 million Americans. This estimate is low as individuals with glaucoma are often unaware they have the disease. As people live longer, this number will increase to more than 3 million by 2020 with 120,000 becoming blind in the US. This study has already identified several methods to diagnose the disease earlier and to follow it more effectively. Purpose: In the upcoming grant cycle we propose studies that should further characterize glaucomatous loss using visual function specific testing and new analysis techniques to help us prevent the devastating loss of vision that leads to a substantial drop in quality of life. Aims: To further improve measures to detect the onset and progression of glaucoma and to assess treatment effectiveness using psychophysical measures of visual function. Participants: At least 346 patients with primary open angle glaucoma, 209 at risk for vision loss due to the disease and 100 healthy age-matched controls. A mean long-term follow up of over 7 years is already available for 419 patients to assist in analyses of progressive disease. Methods: 1) Evaluation of several visual function specific tests to further understand the underlying damage to retinal cells important for vision and to determine the progressive loss associated with retinal cell dysfunction and death. 2) Implementation of new testing paradigms and analysis techniques to shorten the time necessary to identify progression of glaucoma. Importance: If the aims of this application are achieved, we will improve our understanding of the different underlying pathologies associated with primary open angle glaucoma, be better able to monitor progression and conversely the effectiveness of treatment, and predict the outcome more effectively for a large number of patients. This should lead to significant changes in our concepts of glaucoma, further enhancements of the methods used in clinical practice to diagnose and follow this disease, and improved clinical protocols for clinical trials of glaucoma therapies.